The students from Franklin Middle School go on field trips to the art museum, an old-time town, recycling plant, and zoo, finding and solving mysteries at each place.
When Samantha "Sam" Archer and her friends in the nature club arrive in Yellowstone Park on a school trip, they find that the park superintendent's son may have been kidnapped.
On a science class trip to the aquarium, Catalina "Cat" Duran and her friends discover that two of the seals have been drugged and investigate to discover the person responsible.